Field of the Invention
The present invention relates to a digital broadcast receiver for receiving broadcast of signals of speech and the like in the form of digital data.
Description of the Related Art
With the recent advancement in digitization of transmitted signals, there has been realized even radio broadcasting in digital signals. As one of these systems, there is developed a digital satellite radio (hereinafter called DSR) system. In the DSR system, broadcast signals in digital data from a plurality of broadcasting stations (for example 16 stations for stereo broadcasting, or 32 stations for monaural broadcasting) are time-division multiplexed and subjected to QPSK modulation processing, and thereafter the signals are output over a frequency band of 12 GHz to a broadcasting satellite.
An electric wave from the broadcasting satellite is received through satellite broadcast antennas installed in a centralized receiving station (for example CATV station), installed individually in homes, etc., and supplied, through a broadcast cable or directly from the satellite broadcast antenna, to a DSR receiver and demodulated therein so that the radio broadcast sound signal is output.
Since, as described above, broadcast signals from for example 16 broadcasting stations are multiplexed in one receive frequency (hereinafter called "frequency block"), the DSR receiver is adapted to be able not only to select a frequency block (tuning) but also to select one digital broadcast signal from the selected digital broadcast signals of the channels of 16 stations (channel selection). Accordingly, it is made possible for the users to receive a desired broadcast channel by performing the tuning operation and the channel selecting operation.
In the DSR system, various data are added to the broadcast sound data, such as that indicating the type of broadcast content of each of multiplexed digital broadcast signals (e.g., news, sports, rock music, and classical music; hereinafter called program type information), that indicating discrimination among stereo broadcast/monaural broadcast/sound multiplex broadcast (hereinafter called "channel mode information"), that indicating discrimination between music broadcast and speech broadcast such as sound of voice (hereinafter called M/S mode information), and the like. On the DSR receiver side, it is possible to make various signal reception controlling operation using such information.
In a DSR receiver in general, it is arranged such that, when its frequency block is changed to another frequency block by user's operation, the first channel of the new frequency block is forcedly selected out of channels of its 16 broadcasting stations. (Although, there are 32 stations in the case of monaural broadcast, hereinafter it will be assumed for simplicity that the broadcasting stations multiplexed in one frequency block are 16 stations all for stereo broadcast.)
When the above described program type information is used, if the user designates a desired type of program content, for example "NEWS", in his DSR receiver, the DSR receiver automatically searches the received 16 stations for a channel broadcasting a news program (the broadcast channel whose program type information indicates "news") and selects the channel and outputs its broadcast news program. While such an operation is possible, if it is arranged such that, when the frequency block is changed, the first channel is forcedly selected, it frequently occurs that a broadcast different from the program specified by the user is output because the first channel does not always broadcast for example a news program.
In such case, the user has to select his desired channel by listening to each channel while changing the channels one by one, or has to make an operation anew to specify "NEWS" as the program content, and thus there has been a problem that users have to make such a troublesome operation.
Further, for the user to receive a broadcast of another content of program while he designated a specific program content can confuse the user in operating his receiver.